Ultraviolet Light is used in many industrial and medical applications. We also receive a dose of UV light from sunshine, and while a little UV light is good for you excessive exposure can lead to eye and skin damage.

In this article I will explain how to safely work with ultraviolet light and I’ll show you how to build a UV Index Meter that can accurately measure the level of UV and help keep you safe in the sunshine.

Learn to use the popular nRF24L01 radio modules with an Arduino, using the RadioHead library.

In this article we will conduct several experiments sending data between two Arduinos with the nRF24L01. We will then take what we have learned and build a wireless joystick controller for our robot car!

The HC-SR501 is a Passive Infrared (PIR) motion sensor that is extremely useful. It can be used all by itself or combined with an Arduino or Raspberry Pi

In this article you’ll learn how a PIR sensor works and you’ll build some cool projects using the HC-SR501. You can even make a motion activated camera that will tell you who is stealing your Jelly Beans!

I’m sure you have seen those inexpensive robot car chassis kits, the ones that come with two 6-volt motors. They are great fun and very useful and they even come with a couple of speed encoder disks (those little black circles full of holes). Problem is, no one tells you how to use them!

Let’s resolve that and build a robot car with speed sensors. Along the way we’ll learn how to use Interrupts, a valuable programming technique.